Why would you need to turn the ETTL off? If you are using the ST E2 on it's own then the camera will expose for the conditions. The ETTL works by firing a preflash to measure the light levels, if you don't have a flash then it won't be able to do a preflash!

When you turn on the ST-E2, it automatically put itself into ETTL mode. So far in itself it is not too bad, the problem is that when connected to your camera, whether or not you have a flash setup to work with the ST-E2, the camera automatically assumes you have a flash plugged in with the ST-E2. As such, it impacts the exposure setting the camera will make because the camera will choose the same settings as if a flash was present. So you need to compensate by underexposing in order to get the proper shutter speed.

Looking in the manual of the ST-E2 I was not able to find a way to bybass this.

you can use the custom flash functions on the camera in menu and enable disable fireing the flash etc I think in there is the AF assist only option thats how it works for 580s anyway the 430 should be identical

You wouldn't happen to know how to set it up for that on the 430 would you? I'd need to get my AF Assist beam to start working again, but it would be good information to have =)

In the Flash Control menu (with the flash attached and powered on), set the flash to Disable (top menu item), then under External Flash C.Fns, set the C.Fn for the AF assist lamp (C.Fn to Enable.

You might also check the C.Fn 8 setting on your flash - hold the C.Fn button for 2 s, then arrow to #8, make sure it's enabled. With a setting that can be changed on both the camera and the flash, if they differ the one you set most recently will be used.

I have a question. I will say beforehand that my knowledge both intelectually and as bodily experience with flash and that world to be limited. I have read the postings on this thread, and I think I understand half of it:)

I have a 580 EX II and a 430 EX II. I reason I got the ST-E2 was for its ability to master the other two flashes, and that it would give me the possibility to set the white balance correctly when shooting portraits. The way (at least in my head) that I would get the best white balance was to set up the flashes first, then to use an expodisc or if I had forgotten to bring it, a white/grey paper next to the subjects face, and use the ST-E2 to fire it off, while I have the camera and lens next to them to get the most correct reading. Is this a good way to go?

Second. I keep reading here about using the ST-E2 without firing off the flashes.... What some of the postings here say is that it helps with focus assist.. Does it do anything that the AF does not do from the camera at its vantage point? I am a bit confused here. Ar you saying that the ST-E2 and the 580 EX II can help with additional focus readings. Or is this all wrong on my part, and that the focus you are talking about is: reading (focus) to get the right amount of light strenght?

As you can see, I am quite confused here. The use of flash is new to me, since I normally shoot without it. And while I am at it, do you have suggestions for good books to learn the art of lighting, both on an entry level (I have Scott Kelby books on it), and intermediate level books that I can read after the entry level?

I have a 580 EX II and a 430 EX II. I reason I got the ST-E2 was for its ability to master the other two flashes, and that it would give me the possibility to set the white balance correctly when shooting portraits. The way (at least in my head) that I would get the best white balance was to set up the flashes first, then to use an expodisc or if I had forgotten to bring it, a white/grey paper next to the subjects face, and use the ST-E2 to fire it off, while I have the camera and lens next to them to get the most correct reading. Is this a good way to go?

Seems reasonable to me. Personally, I just include a ColorChecker or SpyderCube in one shot of a series, shoot RAW, and set the WB in post.

I keep reading here about using the ST-E2 without firing off the flashes.... What some of the postings here say is that it helps with focus assist.. Does it do anything that the AF does not do from the camera at its vantage point? I am a bit confused here. Ar you saying that the ST-E2 and the 580 EX II can help with additional focus readings. Or is this all wrong on my part, and that the focus you are talking about is: reading (focus) to get the right amount of light strenght?

The ST-E2, 600EX-RT, 580, and 430 flashes have a focus assist lamp - they project a deep red grid pattern of light that gives the AF system something to lock onto in dim light. Other flashes (320EX, 270EX, popup flashes) provide the assist by flashing the main strobe light, which many (including me) find distracting and annoying. FWIW, the new ST-E3 doesn't provide any focus assist.

you can use the custom flash functions on the camera in menu and enable disable fireing the flash etc I think in there is the AF assist only option thats how it works for 580s anyway the 430 should be identical

+1

Disable flash firingEnable AF assist

Your camera will not consider the flash when it meters and your images will be exposed only for ambient light. AND, you'll get the benefit of the AF beam. This can be done with the 580EXII, and the ST-E2. Don't know about the 430EXII, since I've never tested it.

I have a 580 EX II and a 430 EX II. I reason I got the ST-E2 was for its ability to master the other two flashes, and that it would give me the possibility to set the white balance correctly when shooting portraits. The way (at least in my head) that I would get the best white balance was to set up the flashes first, then to use an expodisc or if I had forgotten to bring it, a white/grey paper next to the subjects face, and use the ST-E2 to fire it off, while I have the camera and lens next to them to get the most correct reading. Is this a good way to go?

Seems reasonable to me. Personally, I just include a ColorChecker or SpyderCube in one shot of a series, shoot RAW, and set the WB in post.

I keep reading here about using the ST-E2 without firing off the flashes.... What some of the postings here say is that it helps with focus assist.. Does it do anything that the AF does not do from the camera at its vantage point? I am a bit confused here. Ar you saying that the ST-E2 and the 580 EX II can help with additional focus readings. Or is this all wrong on my part, and that the focus you are talking about is: reading (focus) to get the right amount of light strenght?

The ST-E2, 600EX-RT, 580, and 430 flashes have a focus assist lamp - they project a deep red grid pattern of light that gives the AF system something to lock onto in dim light. Other flashes (320EX, 270EX, popup flashes) provide the assist by flashing the main strobe light, which many (including me) find distracting and annoying. FWIW, the new ST-E3 doesn't provide any focus assist.

Thank you Neuro and justsomeguy. That helps.

while I have you here.... A friend of mine and I did some shooting the other night (picture inclued below) and he did something that I never saw before. We used my gear and the ST-E2 was on, and he pushed the button normally used for dof at the front of the 5D mk II and the flash gave continous light. He said that he does this seldom given that it might shorten the flashs' lifespan. Is this true? Because to me, this is an excellent help in order to see if I have placed my flashes correct. I don't mind burning through batteries, but would mind to kill my flashes:)

[A friend of mine and I did some shooting the other night (picture inclued below) and he did something that I never saw before. We used my gear and the ST-E2 was on, and he pushed the button normally used for dof at the front of the 5D mk II and the flash gave continous light. He said that he does this seldom given that it might shorten the flashs' lifespan. Is this true? Because to me, this is an excellent help in order to see if I have placed my flashes correct. I don't mind burning through batteries, but would mind to kill my flashes:)

It's called modeling flash, can be turned on/off in C.Fn's. IIRC, the manual warns against doing it more than 10 times in a row, and in that case it needs a 10 minute rest.

[A friend of mine and I did some shooting the other night (picture inclued below) and he did something that I never saw before. We used my gear and the ST-E2 was on, and he pushed the button normally used for dof at the front of the 5D mk II and the flash gave continous light. He said that he does this seldom given that it might shorten the flashs' lifespan. Is this true? Because to me, this is an excellent help in order to see if I have placed my flashes correct. I don't mind burning through batteries, but would mind to kill my flashes:)

It's called modeling flash, can be turned on/off in C.Fn's. IIRC, the manual warns against doing it more than 10 times in a row, and in that case it needs a 10 minute rest.

Thank you Neuro. So basically you're saying is that my friend is correct, as far as killing the flash with too much use.

Too much of a specific kind of use, yes. There's a similar warning for using the 580 with an external power pack. The bottom line is that with use, the flash tube gets hot, and if it gets too hot it suffers damage.